Why would a nighttime mouth guard warn you against using it if you have tmj?

If..: If this is an over the counter type mouthgauard, it may be designed only for protecting the teeth. Many studies have shown worsening of symptoms of TMJ using over the counter type guards. They dont fit well and are not adjusted to your dentition. Its best to get a custom guard from your dentist.

OTC ignorance: When purchasing products otc that are not custom made, you run the risk of increasing your symptoms. Otc nighttime mouthguards are often too think and may cause the muscles to go into spasm. Also, the otc mouthguards may alter your bite over a period of time, causing a tmj/tmd issue to develop.

Soft appliance: I agree with the 2 other doctors and would add that due to the fact that these appliances need to be soft to be self adjustable, is a problem. Research has shown that soft appliances may increase the chances of patients to engage in sleep and daytime clenching and grinding. It is like having a piece of gum in your mouth. Increases the urge to chew on it.

Complex problem: TMD are complex. Have a TMJ expert guide your treatment choices. Any dentist can be a TMJ expert with the proper training and experience. Most commonly, oral surgeons, prosthodontists, and orofacial pain specialists. Ask your MD, your dentist and your dental society for referrals.

Recommended: There are no complications involved in using night guard other than issues resulting from improper cleaning. See an Orofacial Pain specialist for custom made mouth night guard. Take care.